The invention relates to monitoring methods, and particularly to methods of monitoring efficiency of air-blowing devices.
FIG. 1 shows a conventional air-blowing device 100, which connects to an equipment 300 with a pipe 110 and to a stack 200 with a pipe 120. Fume exhaust gas in the equipment 300 is drawn by air-blowing device 100, and exhausted through the pipe 110, pipe 120, and the stack 200.
When a factory is built, air-blowing device performance (flow rate, pressure drop etc.) exactly fit the air-blowing requirement of the factory, according to the quantity of fume exhaust gas produced. As all equipments in the factory operate simultaneously, the air-blowing devices are activated with highest current frequency and optimal efficiency. However, the equipment do not always all operate simultaneously. When some of the equipment shuts down, the amount of fume exhaust gas decreases, and the activating current frequency should decrease accordingly to reduce energy consumption and improve operating efficiency.
However, adjustment of the activating current frequency cannot achieve high efficiency without feedback control. FIG. 1b shows air-blowing devices 100, 100′ and 100″, disposed in a ventilation system. Air-blowing devices 100, 100′ and 100″ remove fume exhaust gas from the equipment 300 through the pipe 110 (comprising pipes 111, 112, and 113) and the stack 200. However, distances between the pipe 111 and the air-blowing devices 100, 100′ and 100″ are different; thus, the operating efficiencies of the air-blowing devices are different. For example, air-blowing device 100 may have better efficiency than air-blowing devices 100′. Therefore, to improve efficiency, the activating current frequency of the air-blowing devices should be adjusted separately according to feedback monitoring information.